Electron Impact Excitation of O III: An Assessment

TL;DR

This paper assesses the accuracy of existing atomic data for O III's electron impact excitation, highlighting discrepancies in collision strengths and advocating for new calculations using different computational methods.

Contribution

It provides an independent evaluation of collision strengths for O III and recommends new calculations to improve data accuracy.

Findings

Existing data for collision strengths show inconsistencies.

Energy levels and A-values are accurate in previous studies.

New calculations are needed for reliable collision data.

Abstract

Tayal and Zatsarinny [Astrophys. J. 850 (2017) 147] have reported results for energy levels, radiative rates (A-values), lifetimes, and effective collision strengths ($\Upsilon$) for transitions among 202 levels of C-like O~III. For the calculations they have adopted the multi-configuration Hartree-Fock (MCHF) code for the energy levels and A-values, and B-spline $R$-matrix (BSR) code for $\Upsilon$. Their reported results cover a (much) larger range of levels/transitions than generally available in the literature, and appear to be accurate for energy levels and A-values. However, the magnitude and behaviour of $\Upsilon$ do not appear to be correct for several transitions. We demonstrate this through our independent calculations by adopting the flexible atomic code (FAC) and recommend a fresh calculation for this important ion.